Vacuum-tube socket



Nov.- 29, 1927. 1,651,257-

H. C. DAVIS VACUUM TUBE SOCKET Filed Match 14, 1927 INVENTOR HARRY C.DAVIS BY m ATTORNEY WITNESSES Patented Nov. 29, 1912.7,

UNITED STATES HARRY G. DAVIS, OF BRIGHTON, MASfiACI-IUSETTS.

VACUUM-TUBE sooner.

Application filed March 14, 1927. Serial No. 175,283.

The present invention is concerned with the provision of a vacuum tubesocket in which is incorporated a rheostat of the compression type sothat the voltage of the filament circuit may be regulated with absoluteaccuracy in the case of each individual tube.

Thus the rheostat may be eliminated as a unit part of a radio set andreplaced by an exact filament voltage regulator associated with eachtube. Considering the individual characteristics of vacuum tubefilaments and the degree of variation caused by use, maximum efficiencycan only be obtained by the use of a variable resistor of this type.

An object of the present invention is to provide a tube socket of theabove noted character which will be substantially conventional inappearance and well suited to the requirements of economicalmanufacture.

Another object is to provide a device so constructed that the resistormay be accurately adjusted with expedition and facility, and which willbe rugged, durable and elfi cient in use.

With the above noted and other objects in view, the invention consistsin certain novel features of construction and combinations andarrangements of parts as will be more fully hereinafter set forth andpointed out in the claims. The invention may be more fully understoodfrom the following descrip tion in connection with the accompanyingdrawings, wherein-- Fig. 1 is a view in side elevation of asocketembodying the invention.

Fig. 2 is a top plan view thereof.

Fig. 3 is a bottom plan view thereof.

Fig. 4 is an enlarged sectional detail through the rheostat on the lineH of Fig. 2.

In the drawings I have used the reference character 10 to designate thebase or body of the device supported on the usual legs 11 and includinga centrally raised boss 12 on which a conventional vacuum tube (notshown) is adapted to rest, the tube contacts passing through openings 13in the boss and base and engaging the spring terminal fingers 14, 15, 16and 17 lying against the under face of the base.

Preferably three of the terminal fingers are anchored to three cornersof the plate by screws 18 retained by lock nuts 19 and carry ing bindingnuts 20 for the attachment of wires (not shown), and carrying also lugs21 to which electrical connectors may be soldered if such a connectionis desired instead of that afforded by thebinding posts.

The grid circuit is completed through terminals 14 and 15 and theilament circuit through terminal 16 at the minus side, and the terminal17 at the plus side, the latter terminal finger being associated withthe resistor element in a manner which I shall now describe.

Finger 17 instead of being held by a screw is bent around a hollowdepending cylindrical extension 85 of the base plate 10 and anchored bya pin 22 projecting inwardly through the bottom of the extension Thispin is in electrical contact with a brass disc 23 molded. in the bottomof the cylinder. Fitting the cylinder and stacked upon the disc are aseries of oppositely facing dished carbon discs 24: surmounted by abrass disc 25 against which any desired pressure may be exerted by ascrew 26. This screw threaded through a conductive closure plate 27 forthe open upper end of cylinder 35, the plate being retained in place byscrews 28 or other suitable means. A binding nut 29 threaded onto anupstanding extension 30 of plate 27 preferably clamps a plate 31carrying a solder lug 32 in position so that either a wire or a solderedconnection may be used.

A knob 33 or other manually operable handle means is carried by theexposed end of screw 26 and the resistance in the filament circuit maybe conveniently regulated by ad justing the screw to predetermine thecompression of the compression type rheostat formed by the carbons.

Obviously other forms of bases, sockets and contacts might be used andother material used in the formation of the rheostat if desired,although I find the carbon discs quite satisfactory.

In fact, various changes and alterations might be made in the generalform and arrangement of the parts described withoutdeparting from theinvention. Hence I do not wish to limit myself to the details set forth,but shall consider myself at liberty to make such changes andalterations as fairly fall within the spirit and scope of the appendedclaims.

I claim:

1. A vacuum tube socket including a base block having openings thereinfor the reception of tube terminals and including electrical contactsassociated with said openin said block including ieet one of whichcomprises a hollow cylindrical depending extension, at rheostat housedin said extension, :1 cover for the extension and 'rheosta't adjustingmeans carried by the cover.

2. A vacuum tube socket, including a base block having openings thereinfor the reception of tube terminals, electrical contacts associated Withthe openings, said block including feet, one of which comprises a hoi-10 10W cylindrical depending extension and a irheostait housed in saidextension.

HARRY O. DAVIS.

